When Charlotte's son Benny learns about the old tradition of the Christmas train parade, he persuades her to try and reignite the Christmas magic that brought together their community and the neighboring towns. They enlist the help of Benny’s teacher, but just as Charlotte thinks she might be falling for him, she finds out that he’s been harboring secrets related to why the parade ended in the first place.

Ryder and the pups are called to Adventure City to stop Mayor Humdinger from turning the bustling metropolis into a state of chaos.